Sihler, A.
New Comparative Grammar of Greek and Latin.
Oxford University Press.
2008.

sargento
m.
(Noun)
"sergeant;" (f.) "battleaxe"
Old Spanish sargente. Borrowed from Old French sergent, from Medieval Latin servientem "servant," originally the accusative of serviens "serving," from the verb servire "to serve" (see servir).
The use of sargenta to indicate "battleaxe" derives from an old custom to refer to the feminine form of typically male professions in insulting overtones.
Indo-European

In Proto-Indo-European, *s(u̯)e- meant "peculiar to oneself." Derivations from *su̯e- thus connote distinctiveness from other things. Benveniste (1973) writes, "This duality survived, as is revealed by the etymology, in the two forms se of Latin, which have become independent; the reflexive se, indicating “self,” and the separative se-, sed ‘but’, marking distinction and opposition."

de Vaan, M.
Etymological Dictionary of Latin and Other Italic Languages.
BRILL.
2014.